TY - CONF
A1 - Schneider, André
A1 - Gumenyuk, Andrey
A1 - Rethmeier, Michael
T1 - Laser beam welding of thick materials under the influence of local reduced ambient pressure
N2 - The development of the vapour plume during the laser beam welding of metals with propagation directions along the laser beam axis leads to a reduction of the absorbed laser power in the keyhole. The main reasons are the scattering of the laser radiation on the condensed phase of metallic vapour as well as the defocusing of the laser beam due to the density gradient in the vapour plume. These unfavourable effects can be significantly mitigated by the application of a reduced ambient pressure thus decreasing the interaction between the laser beam and evaporation products, which leads to more stable welding process and results in increased penetration depth, as known from previous studies. A conventional technique use a vacuum chamber principle, similar to that, used for electron beam welding. Application of this technique is restricted by the chamber size and reduces thus the advantages of this approach especially for large components. We demonstrate a possibility of mobile local vacuum application, which allows to generate a reduced pressure only in small region around the keyhole. By using of specially designed mobile pressure lock which can be moved along the welding direction absolute pressure of around 200 mbar could be obtained. This is sufficient to increase the welding depth by around 50%. Coupons from S355 were welded with an incremental laser power from 5 kW to 12 kW at atmospheric pressure and compared to those welded at ambient pressure of 200 mbar. The evaluation of the longitudinal section revealed an increase of the welding depth by about 35%. Furthermore, the welding trials in butt joint configuration on 15 mm thick plates at various laser beam power performed for atmospheric and reduced ambient pressure of around 200 mbar. The increase in welding depth up to 40% was established for reduced pressure. Particularly, low welding speeds under reduced pressure were especially advantageous in terms of increasing the welding depth.
T2 - VIII BTLA 2015 - 8th International conference "Beam technologies & laser application"
CY - St. Petersburg, Russia
DA - 21.09.2015
KW - High power laser beam welding
KW - Mobile vacuum
KW - Local reduced pressure
KW - Vapour plume
KW - Keyhole
PY - 2015
SP - 45
EP - 46
AN - OPUS4-34973
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schneider, André
A1 - Gumenyuk, Andrey
A1 - Rethmeier, Michael
T1 - Mobile vacuum device for laser beam welding of thick materials
N2 - The development of the vapour plume during the laser beam welding of metals with propagation directions along the laser beam axis leads to a reduction of the absorbed laser power in the keyhole. These unfavourable effects can be significantly mitigated by the application of a reduced ambient pressure thus decreasing the interaction between the laser beam and evaporation products, which leads to more stable welding process and results in increased penetration depth. A conventional technique use a vacuum chamber principle, similar to that, used for electron beam welding. Application of this technique is restricted by the camera size and reduces thus the advantages of this approach especially for large components. We demonstrate a possibility of mobile local vacuum application, which allows to generate a reduced pressure only in small region around the keyhole. By using of specially designed mobile pressure lock which can be moved along the welding direction absolute pressure of around 200 mbar could be obtained. This is sufficient to increase the welding depth by around 50%. Coupons from S355 were welded with an incremental laser power from 5 kW to 12 kW at atmospheric pressure and compared to those welded at ambient pressure of 200 mbar. The evaluation of the longitudinal section revealed an increase of the welding depth by about 35%. Furthermore, the welding trials in butt joint configuration on 15 mm thick plates at various laser beam power performed for atmospheric and reduced ambient pressure of around 200 mbar. The increase in welding depth up to 40% was established for reduced pressure. Particularly, low welding speeds under reduced pressure were especially advantageous in terms of increasing the welding depth.
T2 - 3rd International conference in Africa and Asia "Welding and failure analysis of engineering materials"
CY - Luxor, Egypt
DA - 02.11.2015
KW - High power laser beam welding
KW - Mobile vacuum
KW - Local reduced pressure
KW - Vapour plume
KW - Keyhole
PY - 2015
SP - 1
EP - 7
AN - OPUS4-35094
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schneider, André
A1 - Gumenyuk, Andrey
A1 - Rethmeier, Michael
T1 - Mobile vacuum in pocket format, mobile local low-pressure cap for high power laser beam welding of thick materials
N2 - The presented apparatus enables laser beam welding of thick materials under local reduced pressure conditions, thus improving the quality of welds and reducing the laser beam power necessary for complete penetration welding. The vacuum cap presented in this article uses a local reduced ambient pressure environment in a tight zone around the welding area and, in contrast to a conventional vacuum chamber, it is movable in the welding direction. The mobile installation is very compact and reaches pressure values of around 200 mbar. The reduced pressure in the vacuum cap is sufficient to generate 50 % higher penetration depth in comparison to welding under ambient pressure conditions. The low pressure around the keyhole reduces the vapour-plasma plume and therefore prevents a defocusing and scattering of the laser radiation. This allows to raise the amount of laser beam power entering the keyhole as well as the effective power density.
KW - High power laser beam welding
KW - Mobile vacuum
KW - Local reduced pressure
KW - Vapor plume
KW - Keyhole
PY - 2015
U6 - http://dx.doi.org/10.1002/latj.201500025
SN - 1613-7728
SN - 1863-9119
VL - 12
IS - 4
SP - 43
EP - 44
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-34583
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -